About 2 weeks ago I replaced the motor mounts and tranny mount with poly replacements. Now I was expecting a decent amount of vibration to be noticed, but the vibration I have is almost unbearable. My entire center console and radio area on the dash sound like its going to come apart. This only happens after the car is warmed up and only in the 2200-2500 rpm range.

I was looking for input from anyone else that replaced these mounts and what kind of vibrations you are getting. Is this much vibration normal for this upgrade? Is there some sort of break in period for these? The stock mounts were absolutely shot and I could almost twist them in half.

I had these on my mustang back when I had that and the vibrations wernt near as bad, but then again I swapped those in placer of solid mounts, so anything was better than them.

I haven't done poly mounts on the motor, but I did have a vibration from the trams mount install on my old Z. Mine was at highway speeds, but it can occur in other ranges. Are you using the Energy Suspension mount on the trans? If so, I found a trick that I used on my TA, which has caused no vibration this time around.

If your trans mount has a plate that goes between it and the crossmember, and the mount has a nub on the side that faces the trans, you can omit the plate and grind off the nub. If you search, there should be an old thread explaining it in more detail. It was years ago, so might take some time. If you don't find it, I can provide more detail.

Yes. I did install the preload plate, which since it would make the trans sit up higher and throw off the driveshaft angle a lil, im thinking thats whats causing it. The mount I put on there is the energy suspension #3.1142g. Which is specific to the 4th gen cars, it has the correct height mount for the application. Im gona take out the plate this weekend and see if the vibration goes away. Worst case, I have to shim the crossmember down a bit.